They will try to separate you from your family and friends.
They will make you feel selfish or bad for taking care of yourself.
They will alternately give you and withhold sex and affection according to whether you are following their orders sufficiently or not.
They will feel free to check up on you, read your personal emails, etc. but would not tolerate for an instant you trying to do that to them.
That is true its your instinct...But saying that to you if you figured he was,would you leave him,iv being down this road before and trust me it only gets worse.
If you must ask, you must also know that it is happening, already.
It is "how you feel" to you;Therefore you know the signs. Now it is up to you to decide if you are going to waste your time trying to prove it or make the changes necessary NOT to feel that way any longer.
The reason why I put it that way is do to my experience. I have spent 15 years of my 28 year relationship feeling that way. Each year of those 15 years, I have not only been unsuccessful in proving that, but have also convinced myself that even the first 13 years it was happening, but I wouldn't accept it. Now I am no closer to validating my fears and that much closer than being a basket case.
Listen to your gut instinct...it never lies.
Things to manipulate
Isolation e.g. separating you from your family this can help by no one making you realise whats happening
Guilt e.g. making you feel bad if you don't do it this can help but also puts you in depression
Pleasure e.g. giving prizes for you if you do something this can help by making you just go do what they say without thinking
And other methods
To manipulate you, the person needs to think along the lines of, 'If I do X, it will make him do Y. Often the person doing the manipulating doesnt realise thats what they are doing, they are just trying to get through life as best they can, using the assets as they see them, to their best advantage. So its not always cold and calculating by any means. An example of manipulation may be 'If I pretend to be ill, he will have to cancel his evening plans and stay in with me'. I kind of agree with fetish27 that if you feel manipulated, you probably are being.
Sounds like you have good insight into this, that their neediness is driving what appears like quite negative behaviour. Happily the solution does not lie with them, but with you, something needs to change, and you can do it.